Repuguy

Well decided I'd keep the car, and start getting it roadworthy.

So far I've taken everything in the engine bay attached to the motor off of it, and am prepping it for removal. It has no compression on the second rotor, on any face and is likely shot.

I've rebuilt the Nikki, quite fun that.

And I've went ahead and ported the secondary irons on the spare motor with the Pineapple racing Large Street Port.

I'm getting ready to do the housings next, but I cannot seem to figure how a straight piece of metal (the template) is supposed to sit flush to a curved housing without bending it?

I've put up a few pics to show what's going on. It should show the car, the ports before, during, and finally finished on the irons. I've never ported anything before, but I think they look ok for a first time.

Qingdao

iTrader: (3)

I'm not familiar with using a templet on housings. Housings are pretty strait forward. Just open and closure points. So make the opening when you want it to open and make it close when you wan it to close. Think of it like an exhaust cam.

I see you used a whizz wheel on your irons. be carful doing that. You can remove the nitride layer when you cut away at the metal below.

Repuguy

Ah that makes sense. I was mostly trying to keep the timing sane, but increase the flow by widening the port, right?

I'm going to email pineapple, and see what they recommend regarding the use of the template anyway, oddly it has virtually no instructions...

Whizz Wheel? If you're referring to the flat surface of the irons, I only used a sanding block and some 1000 grit paper. there was corrosion on the face that had to be removed. I do understand about the coating/nitriding though, and only went far enough to remove the corrosion, hopefully!

As this isn't going to be a daily driver, and is carbed, do you think it's worth it to port the primaries with the same port shape as the secondaries? I'm thinking the primaries on the carb might not flow enough to satisfy the port and velocity will suffer if I do.

Qingdao

iTrader: (3)

Put the two housings side by side and use a strait edge to mark your port open and closing. That will keep them accurate enough.

Keeping the exhaust open for a longer time is important for a turbo car. On N/A you'll have to consult a more knowledgeable mind. However, wider helps, but keep in mind you have coolant passages there too. Smoothing edges is what I go for more than anything (not polished you need some turbulence)

I wouldn't port the primaries too much. How big are your primary venturies on the Nikki?

Kdo58

There is a YouTube video that shows how to do all the porting,

Repuguy

Oh thanks for the video. I kinda figured it out myself, mostly through this site.

Right now it's a stock Nikki, with stock bleeds and jets. No hogging, all the smog crap on it, but freshly rebuilt. I'm not sure if I'd be overporting the engine if I ported the primaries, making it a dog. It's not going to be a daily, so power is a concern. I'm aiming for 150.

Oh Pineapple got back to me, you just sorta flex the plate until it lines up wit the housing surface. And the little felt washers are spaces so it fits the 12a or 13b housings.

Qingdao

iTrader: (3)

You're gonna want to hog the venturies. Just think your OEM hole isn't but 22mm or so (I can't recall exactly). It is only able to move that much air. 24 or 25mm is conservative and will give you much more air movement.

BUT it also depends on your intake manifold. Some of the Nikki manifolds are really narrow like my 84's. I'm in the process of using a Racing Beat Holley manifold and adapting it to fit my Nikki. Then I can really ruin my clutch in a heartbeat.

Repuguy

Hmm, that makes sense. I have a second Nikki, unknown condition, that's been converted to mechanical secondaries and de-smogged. I also happen to have an early (I think) 12a manifold with no air pump doohickey, and no egr/heat riser port. Should I use this manifold for better performance?


I think I'll measure the mechanical carb (looks like it's off an SA, maybe) and see if it's been hogged out. I'd have to re-disassemble my rebuilt carb to hog it out right?

Is there an easy way to tell the generations of manifold and carburetor, i.e. part numbers? I'm used to the Muscle car and Honda world where this sort of stuff is easy.

My plan, as of now, is to run the car on e-85 (will be replacing all rubber fuel lines anyway as they're cracked) so that it will dramatically reduce the emissions, even without the air pump hooked up (may have to hook it up for show).

Thanks for being so patient with my n00b questions.

Qingdao

iTrader: (3)

^^^ gonna have to seek a higher power for the specific Nikki questions. I typically just use what looks like it has the biggest holes.


Yeah, gotta disassemble the carb and nock the venturies out with something to hog them.


OH you have smog to worry about? Yeah, I don't think any of this will pass emissions. But I don't know the first thing about emissions testing except if it comes up for vote to say "OVER MY DEAD BODY"

Repuguy

Unfortunately CO is one of those states that does do smog. It used to only be in Denver proper, but now is almost the entire state. On the upside, e-85 is plentiful. And for reference, my old BB6 Prelude was coating its rear bumper in black oil/carbon due to worn rings and still easily passed smog. So in a freshly rebuilt rotary with good plugs, timing, seals, ect I'm pretty sure I can pass smog.

I'll have to think about the whole remove the venturies thing. Maybe I'll just mess with the spare carb and get this one running first.

Our air quality in CO is among the worst in the nation for particulates, unfortunately. So I don't really want to contribute to that. But interestingly if you look into the data a huge portion of total emissions comes form our oil and gas exploration, and only a tiny bit from cars. Even less from older cars. Not sure wtf is up with having to meet tougher emissions than CA...No 25 year rolling deadline, it's a hard one at 1975! Sorry to go off topic.

I think I'll just clean up the primaries on the center iron for now.

Qingdao

iTrader: (3)

^^^there ya go. One hot carb and one DD carb.

Repuguy

Here's some pics of the mechanical/modded carb and the really odd manifold. There seems to be no provisions for EGR on this manifold nor O2 to the cats. I placed the manifold spacer plastic thing from my rx7 over the manifold on the mystery one, and the holes all line up, and aren't any larger or smaller, but the manifold itself is notably lighter. It's obviously been monkeyed around with, but maybe it's worth saving?

Repuguy

Uhoh...I took my manifold gasket out today to check the fit of center iron. I have a Y marked iron, apparently it has the large ports! The gasket for the intake is way of now! So Should I port the non ACV intake to fit the ports and then cut the gasket? That leaves me with filling in the ACV hole on the iron too though. Kinda stuck, advice would be appreciated.

Jeff20B

iTrader: (13)

Good lord.

Jeff20B

iTrader: (13)

Ahem. You are making all kinds of rookie mistakes. I'll see if I can get through this in a coherent, understandable way.

Your intake gasket is a bad paper material. Looks to be from an aftermarket kit. Get a proper OEM style gasket from Mazdatrix.
DO NOT port the intake manifold! It is that size in the runners for a reason.
FILL the intermediate plate's ACV port with quicksteel or JB weld putty. The metal must be clean. You are calling it an EGR port which it is not.
Your stock Nikki has 20mm primaries which are too small for a stockported 12A. you want at least 24mm.
Your engine intake ports are probably too big. You probably hogged the runners too.
The modded Nikki you have there was set of poorly. I know this because it is rare to find one that was set up well, as it is a difficult carb to work on.

Anything else I might have missed? I'm sure there is but I've given you some things to mull over. Oh, there is one more thing. This setup will not pass emissions. You need a virtually 100% stock car with all devices working for that. Say hello to 101HP.

Repuguy

Thank you Jeff! I figured I was making some mistakes. It's nice to have a pro tell you you're doing something wrong.

I've only touched the secondaries, not the primaries, as I'd read they were too big from the factory. I'm going to nix the porting the intake as well, thanks. Just seemed bizzare that the iron side is so much larger than the gasket, and the intake.

Ah, if I stay with the stock, emissions manifold, it seems to line up with the ACV port. Does blocking it of affect emissions, after the engine is warmed up? I know it will have higher emissions when cold.

Hmm, I thought the primaries looked tiny on the Nikki. I'm not sure how to port them out yet, without loosing the proper venturi shape though. I know if you loose that shape, the carb won't draw fuel.

Thankfully I haven't toughed the runners (The secondaries) beyond what I'd call a bowl, only enough with sanding paper to get the burning carbon smell, and a casting goober or 2.

Yep that other carb looks hacked, so I think I'll stick with the stock carb with stock jets (checked the FSM and they all match stock for the year) with new gaskets and needles( I checked as best I could for needle operation, and they seem fine so far).

I'd be surprised if it didn't pass emissions. Hell my old 71 ford with bad valves, and a cam, passed easily. My Prelude, shooting carbon and oil out the exhaust passed, so maybe the 7 will as well? If not, I'll have to search out the solenoids that are broken.

Seriously, thanks again for the help!

Qingdao

iTrader: (3)

Cut your venutries by hand. Yes, they have to be hourglass shaped, but it's not a ridiculously accurate procedure.


Rotary's don't reuse the air fuel mix as piston engines do. It makes them difficult to pass emission things. Do you have all of your catalytic converters? Air pump? Carbon canisters and all the stuff Mazda did to try to get it to just barely pass in the 80s? This is the least smog/emissions ;friendly engine ever created ever.

Repuguy

You think cutting them by hand is safe? Hmm, I will have to read more on how to do it before I'm comfortable. At least I have 2 sets of venturies.

By reuse, do you mean EGR, or just port and valve timing sort of stuff? Kinda lost. Anyway I think I see what you mean, especially considering event overlap when the apex passes over the exhaust port and the intake charge and exhaust could mix. RX8 design makes a lot more sense now.

I do have all the stock smog stuff as far as I can tell. I am missing the very first solenoid in the rats nest! I think it's the one that controls Leading spark advance. Smog pump is there, and seems to move air, when turned by hand. Cats look to be present, but unsure of their condition. I bought the car as a non-runner, so I have no yardstick to measure by.

I never saw the engine I'm working with assembled, it was a series of parts in the back of the car along with 3/4ths of a gasket set lmao. There's another engine IN the engine bay, but I'm guessing it's shot due to bad compression test.

Wow, sorry if that sounds like complaining. Just realizing I'm not conveying very well what I'm doing, and where I'm starting from. I'm used to being able to look up part numbers, and other easy refs and parts availability from the Ford world. This rotary stuff is all new.

BTW, my daily driver is only 90hp, but weights 300 pounds less than the 7, so I'm used to low torque low HP fun cars.

Qingdao

iTrader: (3)

yeah, cutting by hand is safe. Hand cut venturies work on my car. Just make the peak thickness at the little hole on the venturi. You'll know what I'm talking about when you bang it out.


I've never had an 8 apart. I don't know if they overlap too much, but what I mean is not overlap rather re combusting the gasses in the combustion chamber.

As a piston makes a down stroke it pulls in a volume of air/fuel. It compresses, ignites and exhausts. But some of the residual air/fuel is left in the combustion chamber for the next cycle. Rotary engines have no way to do this. all the air/fuel is cramed out of the chamber and you start fresh. Hence the flame ***** that come out of the exhaust on RX7s. This is just one of the reasons why rotaries are not good at passing emissions, but great at scaring tailgaters.

Also, long combustion chambers are difficult to get complete burn of all of the air/fuel mix. and the list goes on and on and on.

On the other side of the coin when Honda released its car engines to America; American standards had new regulations on emissions. American car manufactures were putting two or three cats to try to meet the strict new guidelines (I think GM just ended up cheating like VW did recently). The Honda engine was clean enough to not need any cats whatsoever to pass.



Bore those venturies out, get a long primary exhaust, and a direct fire igniton and you'll toss that dd to the curb.

Repuguy

Makes sense why they don't pass emissions, kinda like a 2-stroke, but bigger. I'll start taking my carb back apart now lmao.

I went out to check my rotor housings to refresh my memory, and I think I may be screwed, there seems to be a good bit of flaking of the chrome on one of them. The other only has a tiny bit of flaking.

I also posted a pic of what a large street port template looks like from Pineapple Racing. It seems to me, that I read somewhere to NEVER cut downwards on the exhaust port opening? But the template clearly wants you to port downward. Looks like someone's put a small bevel on the housing before I even got it in my hands.

What do you guys think?

Qingdao

iTrader: (3)

Two strokes resonate exhaust gasses back into the combustion chamber rotaries are complete loss. Regardless of how you look at it understand that getting a rotary to pass emissions is a challenge.

Where is that chrome flaking? Is it in a compression area, looks like it. Doesn't look too terrible, but it looks like its in a bad location.


Cutting downward on the housing will open your exhaust up earlier. Just like cutting the exhaust ports higher on a two stroke. So the more you cut toward the combustion area the shorter you will give your power stroke time to work, but the faster you can get rid of the exhausting gasses.

If it was me and I knew for sure the plate was positioned correctly, I'd go with what Pineapple Racing said to cut. Figure they know something I don't.

Repuguy

Yeah forgot about that complete loss thing. I was referring more to how they're so sensitive seemingly to exhaust restriction. Hopefully the cats are up to snuff. If not Hhigh flow cats will go in (need to research more on that first).

It's flaking int he area between the leading plug hole and the exhaust port; I think most of them flake there? I can't believe you can run an engine with that much damage inside of it? Maybe rotaries are more tolerant of surface variations than piston engines?

Yeah that makes sense, it make the port open earlier, but leaves less time for the power 'stroke'. So loose some low end, gain top end due to flow and timing. Still seems scary to cut that way. The template seems to indicate an area below the exhaust sleeve itself. I don't want to go into the water jacket.

Qingdao

iTrader: (3)

Flaking in the red area is a problem because its where the seal is made when the combustion happens.

The blue not so much.


Use atkins seals, they seem to seal better to less than perfect housings.

Repuguy

Unfortunately, it's in the red area. I'm assuming the red area is where the spark plugs would be? Nice drawing btw. I'm going to pull the second motor, see if it's in any better shape. Those Atkins seals seem expensive? Seal set is roughly half of what I paid for the whole dang car!

So I took my nice 'shiny' rebuilt carb and started tearing it down again. I've gotten one booster venturi out, but the other seems pretty firmly lodged.

More importantly, I know this must sound dumb, but do you hammer/persuade the main venturies out from the top, or the bottom? I'm assuming top because the oil tubes are in the way of knocking the venturies out.

Jeff20B

iTrader: (13)

The oil tubes come out with a chuck from a cordless or corded drill. The three "fingers" can be gently tightened on the soft brass so you can get a grip on there and then twist and pull.

Others have used vice grips which are hell on the brass tube. Speaking of which, did you mar the boosters? Hopefully not. I use a spare junk air bleed threaded in, which I grab with a vice grip, and tap the vice grip upward with a hammer. Works every time.